JP2009283987A - Sensor shield - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To take countermeasures against a bad influence of a liquid in an immersion lithographic apparatus. <P>SOLUTION: The lithographic apparatus includes a supporting structure MT for supporting a pattern providing device MA. The pattern providing device provides a pattern to a radiation beam PB in accordance with a desired pattern. The lithographic apparatus further includes a substrate table WT for supporting a substrate; a projection system PL for projecting a pattern-provided beam to a target portion of the substrate W; a measurement system for measuring a parameter of (a) the substrate table, or (b) the substrate, or (c) an image projected by the projection system or (d) a combination of any of (a)-(c); and a liquid supplying system for supplying a liquid to a space between the substrate and the projection system. The lithographic apparatus also includes a shield arranged near one part of the measurement system, and shielding the part of the measurement system from the liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lithographic apparatus, and more particularly to an immersion type lithographic apparatus.

  A lithographic apparatus is a machine that applies a desired pattern onto a substrate (typically its target portion). For example, a lithographic apparatus can be used in the manufacture of integrated circuits (ICs). In this case, in order to form a circuit pattern on each layer of the IC, a pattern applying device, which is also called a mask or a focusing screen, is used. This pattern is imaged onto a target portion (eg including part of one or several dies) on a substrate (eg a silicon wafer). The transfer of the pattern is usually performed by forming an image on a layer of a radiation sensitive substance (resist) provided on the substrate. In general, a single substrate will contain a plurality of target portions that are adjacent to one another in a network of target portions that are successively patterned. A known lithographic apparatus scans a pattern in a predetermined direction (scanning direction) through a so-called stepper and a projection beam that irradiates each target portion by exposing the entire pattern to the target portion at once, and at the same time parallel to that direction. A so-called scanner that scans the substrate synchronously in the direction or anti-parallel direction and thereby irradiates each target portion. It is also possible to transfer the pattern from the pattern applying device to the substrate by imprinting the pattern on the substrate.

  In lithographic projection apparatus, it has been proposed to immerse the substrate in a liquid having a relatively high refractive index (eg water) so as to fill the space between the final member of the projection system and the substrate with the liquid. The main point of this method is that, since the exposure radiation will have a short wavelength in the liquid, it is possible to image small features. The effect of the liquid can be viewed as increasing the effective numerical aperture (NA) of the projection system and increasing the depth of focus. Other immersion liquids have been proposed that contain water in which solid particles (eg, quartz) are suspended.

  However, immersing the substrate, or substrate and substrate table, in a liquid bath (see, eg, US Pat. No. 4,509,852, the entire contents of which are incorporated herein by reference) accelerates during scanning exposure. It means that there is a large amount of liquid that must be present. This requires an additional motor, or a more powerful motor, and liquid turbulence can have undesirable and unpredictable results.

  One solution proposed for the liquid supply system is to supply liquid only to a local area of the substrate between the final member of the projection system and the substrate (the substrate generally has a larger area than the final member of the projection system). It is to be. One method proposed as a configuration for this is disclosed in PCT patent application WO 99/49504, the entire contents of which are incorporated herein by reference. As shown in FIGS. 2 and 3, the liquid is supplied onto the substrate by at least one inlet IN, but it is preferable to supply the liquid to the final member along the direction of movement of the substrate. Also, the liquid is excluded from at least one outlet OUT after passing under the projection system. That is, when the substrate is scanned in the − (minus) X direction below the final member, liquid is supplied on the + X side of the final member and removed on the −X side. FIG. 2 schematically shows a structure in which liquid is supplied from an inlet IN and is excluded from the other side of the final member by an outlet OUT connected to a low pressure source. According to FIG. 2, the liquid is supplied along the direction of movement of the substrate relative to the final member, but this need not be the case. The orientation and number of the inlet and outlet positions arranged around the final member can vary and an example is shown in FIG. In FIG. 3, four sets of inlets with outlets on either side are arranged in a regular pattern around the final member.

  In accordance with one aspect of the present invention, a lithographic apparatus is provided. The lithographic apparatus includes a support structure configured to hold the patterning device. The pattern application device is configured to apply a pattern to the radiation beam according to a desired pattern. A lithographic apparatus includes a substrate table configured to hold a substrate, a projection system configured to project a patterned beam onto a target portion of the substrate, and (a) a substrate table, or ( b) a substrate, or (c) an image projected by the projection system, or (d) a measurement system configured to measure parameters relating to any combination of items (a) to (c), a substrate, And a liquid supply system configured to supply liquid to a space between the projection system and the projection system. The lithographic apparatus also includes a shield disposed near the portion of the measurement system and configured to shield the portion of the measurement system from liquid.

  In one embodiment of the present invention, the measurement system includes a sensor. The sensor includes, for example, an alignment sensor, a level sensor, a transmission image sensor, a lens interferometer, or any combination thereof. In one embodiment of the invention, a portion of the sensor includes a fiducial mark provided on the substrate table.

  In one embodiment of the invention, the shield includes a plate disposed on part of the measurement system. A lithographic apparatus may be provided with a robotic arm, which is configured to position the plate on the part of the measurement system and to remove the plate from the part of the measurement system. The plate can be configured to keep the projection system in contact with the liquid as the substrate table is moved from below the projection system. In order to keep the projection system in contact with the liquid, the plate is raised or the release mechanism plate configured to hold the plate is raised or the plate is held or the projection system is kept in contact with the liquid. Therefore, a release mechanism can be provided.

  In one embodiment of the invention, the shield includes a shutter operable to isolate a portion of the measurement system from the liquid. In one embodiment of the present invention, the shutter includes a plate configured to open and close an opening in a void in the substrate table (where the portion of the measurement system is provided in the void). In one embodiment of the present invention, the shutter includes a fan-shaped or compound shutter configured to open and close an opening in a void in the substrate table (where the portion of the measurement system is provided in the void).

  In one embodiment of the invention, the shield includes a gas inlet provided near a portion of the measurement system, which gas inlet is configured to remove gas liquid to substantially remove all liquid near or near the portion of the measurement system. It is configured to generate a jet. In one embodiment of the present invention, the shield includes a vacuum outlet provided near the portion of the measurement system, the vacuum outlet so as to substantially inhale and remove all liquid near the portion of the measurement system. It is configured.

  In another aspect of the present invention, the following device manufacturing method is provided. The method uses a projection system to project a patterned radiation beam through a liquid present between the projection system and the substrate toward a target portion of the substrate, and (a) a substrate table, or ( a portion of a measurement system configured to measure a parameter relating to b) a substrate, or (c) an image projected by a projection system, or (d) any combination of items (a) to (c) Including shielding from liquid.

1 depicts a lithographic apparatus according to one embodiment of the invention. 1 shows a liquid supply system used in a lithographic projection apparatus. 1 shows a liquid supply system used in a lithographic projection apparatus. Figure 3 shows another liquid supply system used in a lithographic projection apparatus. Figure 3 shows another liquid supply system used in a lithographic projection apparatus. 1 shows a lithographic apparatus with a two-stage according to an embodiment of the invention. Fig. 4 illustrates an example of a sensor that can be used to measure the position of an aerial image at a substrate level position. Fig. 2 shows a plate arranged in a tube of fiducial marks provided on a substrate table for shielding the fiducial marks from liquids in a lithographic apparatus according to an embodiment of the invention. Fig. 5 shows a shutter covering a reference mark on a substrate table according to an embodiment of the invention. FIG. 4 illustrates an example of a shutter that can be used to shield a fiducial mark on a substrate table according to one embodiment of the present invention. FIG. 4 shows a gas inlet adapted to form a gas jet to remove all of the liquid from a fiducial mark on a substrate table according to one embodiment of the present invention. Fig. 4 shows a vacuum system adapted to aspirate and remove all of the liquid from a fiducial mark on a substrate table according to one embodiment of the present invention.

  The present invention will now be described by way of example only with reference to the accompanying schematic drawings. In the drawings, the same reference numerals denote the same parts.

FIG. 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. This lithographic apparatus
An irradiation system (irradiation device) IL adapted to condition a radiation beam PB (eg UV radiation or DUV radiation);
A support structure (e.g., configured to support a patterning device (e.g. mask) MA) and coupled to a first positioning means PM configured to accurately position the patterning device according to certain parameters , Mask table) MT,
A substrate table (e.g. a wafer) configured to hold a substrate (e.g. resist-coated wafer) W and coupled to a second positioning means PW configured to accurately position the substrate according to certain parameters.・ Table) WT,
A projection system (for example, a refractive projection lens system) configured to project a pattern imparted to the radiation beam PB by the pattern imparting device MA onto a target portion C (for example, including one or more dies) of the substrate W. Including PL.

  Irradiation systems can be used with various optical components (eg, refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components or the like to direct, shape, or control radiation. Or any combination thereof.

  The support structure supports, ie bears the weight of, the patterning device. The support structure holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, or other conditions (eg, whether the patterning device is held in a vacuum environment, etc.). The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure can be, for example, a frame or table that can be fixed or moved as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. As used herein, the term “focus plate” or “mask” may be considered synonymous with the general term “patterning device”.

  As used herein, the term “patterning device” should be broadly interpreted as referring to any device that can be used to apply a pattern to a cross section of a radiation beam so as to create a pattern on a target portion of a substrate. . It should be noted that the pattern imparted to the radiation beam does not exactly match the desired pattern at the target portion of the substrate, for example if the pattern includes phase shift features, or so-called auxiliary features. In general, the pattern imparted to the radiation beam corresponds to a particular functional layer in a device such as an integrated circuit being formed in a target portion.

  The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. In lithography, masks are well known and include mask types such as binary, alternating phase shift, attenuated phase shift, and various hybrid masks. One example of a programmable mirror array uses a matrix array of small mirrors, where each mirror can be individually tilted to reflect the incoming radiation beam in different directions. These tilted mirrors impart a pattern to the radiation beam reflected by the mirror matrix.

  As used herein, the term “projection system” is appropriate to be used as exposure radiation or to other factors such as the use of immersion fluid or the use of vacuum pressure. As such, refraction, reflection, and refraction and reflection should be broadly interpreted as encompassing various types of projection systems including magnetic, electromagnetic and electrostatic optics, or any combination thereof. I must. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

  The lithographic apparatus described herein is transmissive (eg, employing a transmissive mask). Alternatively, the lithographic apparatus may be reflective (eg, using a programmable mirror array of the kind previously described or using a reflective mask).

  The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such a “multi-stage” machine, additional tables are used in parallel, or one or more tables are used for exposure while one or more tables are preparatory work. You may do it.

  In FIG. 1, the illumination system IL receives a radiation beam from a radiation source SO. For example, if the radiation source is an excimer laser, the radiation source and the lithographic apparatus may be separate. In that case, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is transferred from the radiation source SO to the irradiation device IL, for example by means of a beam supply system BD including a suitable directing mirror and / or beam expander. Sent. In other cases the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The radiation source SO and the irradiation device IL may be referred to as a radiation system together with the beam supply system BD, if necessary.

  The irradiation device IL may include an adjustment device AD that adjusts the angular intensity distribution of the radiation beam. In general, at least the outer radial range and / or the inner radial range (generally referred to as outer σ and inner σ, respectively) in the radial direction of the intensity distribution at the pupil plane of the illuminator can be adjusted. Furthermore, the irradiation device IL can include other various components such as an integrator IN and a condenser CO. The irradiation device is used to condition the radiation beam and to give the desired uniformity and intensity distribution in the cross section.

  The projection beam PB is incident on the patterning device (eg, mask MA), which is held on the support structure (eg, mask table MT), and is patterned by the patterning device. The radiation beam PB traversing the mask MA is transmitted through the projection system PL. This projection system focuses the beam on the target portion C of the substrate W. An immersion hood IH, further described below, supplies immersion liquid to the space between the final member of the projection system PL and the substrate W.

  The second positioning means PW and the position sensor IF (e.g. interferometer, linear encoder or capacitive sensor) ensure that the substrate table WT is accurately positioned, e.g. to position different target portions C in the optical path of the radiation beam PB. Moved. Similarly, for example, after the mask has been mechanically removed from the mask storage location or during scanning, the first positioning means PM and the separate means may be used to accurately position the mask MA with respect to the optical path of the radiation beam PB. Position sensors (not clearly shown in FIG. 1) can be used. In general, the movement of the mask table MT is performed by a long stroke module (coarse positioning) and a short stroke module (fine positioning) that constitute a part of the first positioning means PM. Similarly, the movement of the substrate table WT is performed using a long stroke module and a short stroke module which constitute a part of the second positioning means PW. In the case of a stepper (as opposed to a scanner), the mask table MT is connected or fixed only to the short stroke actuator. Mask MA and substrate W are aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment marks occupy a given target portion as shown, but they are placed in the space between the target portions (they are known as scribe line alignment marks).

  Similarly, when one or more dies are provided on the mask MA, mask alignment marks can be provided between the dies.

  The illustrated apparatus can be used in at least one of the following modes:

1. In step mode, the mask table MT and the substrate table WT remain essentially stationary while the entire pattern imparted to the radiation beam is projected onto the target portion C at one time (ie, a single static exposure). Is done. The substrate table WT is then moved in the X and / or Y direction so that another target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

2. In scan mode, the mask table MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto the target portion C (ie, one dynamic exposure). The speed and direction of the substrate table WT relative to the mask table MT are determined by the magnification (reduction ratio) and image inversion characteristics of the projection system PL. In scan mode, the maximum dimension of the exposure field limits the width of the target portion in one dynamic exposure (non-scanning direction), while the length of the scanning operation determines the height of the target portion (scanning direction). decide.

3. In other modes, the mask table MT is essentially held stationary and holds a programmable patterning device, while the substrate table WT is projected onto the target portion C while the pattern imparted to the radiation beam is projected onto it. Moved or scanned. In this mode, a pulsed radiation source is generally used and the programmable patterning device is updated on demand after each movement of the substrate table WT or during successive emitted light pulses during scanning. . This mode of operation can also be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of the type cited above.

  Combinations of the use modes and / or variations thereof, or also completely different use modes can be employed.

  Another immersion lithography solution with a localized liquid supply system is shown in FIG. Liquid is supplied by two grooved inlets IN on each side of the projection system PL and is removed by a plurality of discontinuous outlets OUT arranged radially outward of the inlets IN. The inlet IN and outlet OUT can be formed in a plate with a hole in the center, through which the projection beam is projected. The liquid is supplied from one grooved inlet IN on one side of the projection system PL, is excluded from a plurality of discontinuous outlets OUT on the other side of the projection system PL, and is thin between the projection system PL and the substrate W. A liquid film stream is formed. The selection of the combination of the inlet IN and the outlet OUT to be used is determined according to the moving direction of the substrate W (other combinations of the inlet IN and the outlet OUT are not effective).

  Another immersion lithography solution with a local liquid supply system proposed so far is a sealing member that extends along at least part of the boundary of the space between the final member of the projection system and the substrate table Is provided in the liquid supply system. This solution is illustrated in FIG. This seal member is substantially stationary with respect to the projection system in the XY plane, but there is some relative movement in the Z direction (the direction of the optical axis). A seal is formed between the seal member and the substrate surface.

  In FIG. 5, the reservoir 11 forms a non-contact seal to the substrate around the image area of the projection system, thereby confining the liquid and creating a space between the substrate surface and the final member of the projection system. It comes to meet. The reservoir is formed by a seal member 12 disposed around the lower side of the final member of the projection system PL. The liquid is guided into the inner space of the seal member 12 below the projection system. The seal member 12 extends slightly above the final member of the projection system, the liquid level rises above the final member, and a buffer solution is formed. The sealing member 12 has an inner peripheral surface, which by way of example can be fully aligned with the shape of the projection system or its final member at the upper end and can be rounded, for example. At the bottom, the inner peripheral surface sufficiently matches the shape of the image area (although not necessarily, for example, a square).

The immersion liquid is confined within the reservoir by a gas seal 16 between the bottom of the seal member 12 and the surface of the substrate W. The gas seal is a gas (eg, air or synthetic air: in the example N ₂ or inert gas) that is supplied in pressure via the inlet 15 to the gap between the sealing member 12 and the substrate via the inlet 15. ) And is extracted through the first outlet 14. The high pressure at the inlet 15, the vacuum level at the first outlet 14, and the gap geometry are adjusted to confine the liquid by creating a fast inward gas flow. Such a system is disclosed in US patent application Ser. No. 10 / 705,783, the entire contents of which are incorporated herein by reference.

  The lithographic apparatus includes one or more stations, at least one of which is an exposure station. For example, FIG. 6 is a plan view of a lithographic apparatus having two stations 30 and 32. In one embodiment, as shown in FIG. 6, two substrate tables WT are moved or exchanged between station 30 (here including the measurement station) and exposure station 32. The exchange of the two substrate tables WT is shown in dotted lines in FIG. 6 and the two substrate tables share the exposure station 32 and the station 30. A great advantage of such a structure is that the throughput can be increased, and during the exposure processing of one substrate, the substrate to be subjected to the next exposure processing is measured. Another possible advantage of such a structure in an immersion lithographic apparatus is that certain operations can be performed in a dry state while exposure is performed in a wet state. For example, leveling and alignment measurements can be advantageously performed using a table at a first position in the absence of immersion liquid, and exposure can be performed at a second position where immersion liquid is present. Can be used and executed. Alternatively, the apparatus can have a single substrate table, in which case the measuring station and the exposure station are placed in one position or in two places, with the substrate table between the stations. Moved.

  In this particular example, the measurement station 30 is at the position of the substrate table WT of the lithographic apparatus, where measurements (such as alignment and / or leveling) of the substrate table WT and / or substrate W are performed. . One or more measurement systems are used at the measurement station 30 and include, for example, measurement sensors 34 (eg, optical encoders, capacitive sensors, level sensors, alignment sensors, etc.). The exposure station 32 is a position in the lithographic apparatus where the substrate W is exposed to radiation that passes through the projection system. In one embodiment, the station 30 may be a pre-alignment station 30 in which, for example, the substrate is typically placed in a lithographic apparatus before the substrate is placed on the substrate table WT by the substrate handling robot. Pre-alignment in the operation room. In general, the station 30 may be almost all locations (one or a plurality of locations) in the lithographic apparatus including the substrate operation chamber.

  One or more measurement systems are used in the lithographic apparatus, for example, relative height of the substrate surface (by level sensor), alignment of the substrate or substrate table (by alignment sensor), or projection by projection system One or more parameters are measured, including aerial image features (by the transfer image sensor) at a specified substrate level position. The measurement system disclosed herein and described in the claims is a parameter relating to one item such as (a) a substrate table, (b) a substrate, or (c) an image projected by a projection system. It is only required that it can be measured. However, it is also conceivable that two or more of the items (a) to (c) are measured. For purposes of this specification, sensors can be classified as one of at least two types of sensors. The first type of sensor should not be used or cannot be used if it becomes wet or damp, for example when an immersion liquid is used in a lithographic apparatus. This first type of sensor includes, for example, a level sensor and an alignment sensor 34. These sensors are used in measurement stations and are referred to as “dry sensors”. The reason for this first type of sensor is that it does not tolerate liquids (and does not function properly) and / or produces accurate or valid results when the sensor is used wet or moist. It includes not giving.

  As used herein, the term sensor refers to a part of the detection system, or a part used in the detection system (eg, a fiducial mark on the surface of the substrate table used by the sensor (see FIG. 6), substrate Sensor parts assembled on the table, or part of the sensor member or radiation source).

  The second type of sensor can be used wet or wet. The second type of sensor is used in exposure of a lithographic apparatus where immersion liquid is present and is therefore referred to as a “wet sensor”. This second type of sensor includes, for example, a transmission image sensor (TIS), a spot sensor, and a lens interferometer (LI) sensor. The LI sensor is an interferometer in the lithographic apparatus that is used to measure the aberrations of the projection system (measurements are used to control the wavelength of the emitted light). FIG. 7 shows an example of a transmission image sensor (TIS). The TIS 40 is a sensor used to measure the position of the projection space image of the mask pattern at the substrate position. The projected image at the substrate level position is a line pattern having a line width suitable for the wavelength of the exposure radiation. This TIS uses a transfer pattern 42 to measure the mask pattern with the lower phototube 44. The phototube 44 generates an analog electrical signal, which is converted to digital data via an analog-to-digital converter ADC. For example, the sensor data can be used to measure the position of the mask relative to the substrate table in six degrees of freedom (three for transmission and three for rotation). Further, the magnification and scale of the projected mask are measured. TIS is also used to measure the optical performance of a lithographic apparatus. Different illumination settings are used in combination with different projection images to measure properties such as pupil plane, coma, spherical aberration, astigmatism, and field curvature.

  In one embodiment, both wet and dry sensors can be used in an immersion lithographic apparatus. When a dry sensor is used in such a device, the sensor may come into contact with the liquid, for example during the operation of applying immersion liquid to a portion of the substrate. When such a dry sensor is wet or used in a damp condition, the dry sensor will not give accurate, proper or effective results.

  For example, the presence of even a small amount of liquid in a dry sensor used to measure the radiation beam can cause reflection and / or refraction, which can lead to false readings. A liquid film present on a dry sensor, such as a fiducial mark on a substrate table, will, for example, cause reflection twice in the liquid film with a radiation beam measurement. The dry sensor is dried and / or shielded from liquid (eg, immersion liquid) to prevent or substantially eliminate the dry sensor from contacting the liquid in the lithographic apparatus. It is advantageous.

  In one embodiment of the present invention, a shield is used to shield a portion of the dry sensor, eg, a fiducial mark on the substrate table that may come into contact with the liquid. For example, as shown in FIG. 8, the plate 50 can be disposed in the tube of the reference mark 34 to shield the reference mark so that it does not come into contact with liquid (such as the liquid in the reservoir 11). For example, the fiducial mark 34 may be moved to a position close to the liquid in the reservoir 11 when replacing the substrate, and thus may get wet.

  The plate 50 is placed on the fiducial mark 34 using, for example, a robotic arm before moving the substrate table to an area of the lithographic apparatus where liquid is present, such as an immersion exposure station 32. Plate 50 is picked up and removed from fiducial mark 34 when a measurement (eg, alignment, leveling, etc.) is performed at measurement station 30.

  Although plate 50 is shown as being used to cover fiducial mark 34, it should be recognized that any other shape and type of shield can be used to isolate fiducial mark 34 from the liquid. . For example, a box or hemisphere can be used to cover the fiducial mark 34.

  In one embodiment, when a closure plate is provided in the lithographic apparatus that is used to keep the projection system in contact with the liquid when the substrate is moved from below the projection system, the closure plate is It can be used as a shield for protecting 34 from coming into contact with the liquid in the reservoir 11.

  In particular, the closing plate 50 carried by the substrate table WT can be used to cover the fiducial mark 34 when the substrate is exposed. When exposure is performed, the closing plate is carried under the opening of the reservoir 11, and the release mechanism is activated to lift or hold the closing plate, thereby covering the opening. The release mechanism may be a magnetic release type or a vacuum release type. For example, the seal member 12 may include a magnet in order to generate a force necessary to bring the closing plate into contact with the seal member 12. Instead, a vacuum outlet can be provided to bring the closing plate 50 into contact with the seal member 12.

  In one embodiment shown in FIG. 9, a shutter 52 is used to cover the fiducial mark 34 to shield the fiducial mark 34. According to this structure, for example, the shutter 52 moves to open and close the void 53 of the substrate table WT provided with the reference mark 34. In order to avoid wetting of the fiducial mark 34, the void can be closed with a shutter when the liquid is in contact with the substrate W during exposure of the substrate. The shutter may be, for example, in the form of a plate (or blade) that is operable to open and close the void 53 of the substrate table WT. The shutter can also be in the form of a fan-shaped compound shutter 54 as shown in FIG. 10 and as seen, for example, with a camera.

  In one embodiment shown in FIG. 11, a gas inlet 55 is provided near the fiducial mark 34 to shield the fiducial mark 34 and combined to remove all of the liquid that may have contacted the fiducial mark 34. A gas jet or gas flow 56 can be generated to eliminate or prevent liquid from attempting to contact the fiducial mark 34. In one embodiment shown in FIG. 12, a vacuum pressure system is provided having an outlet 57 located near the fiducial mark to aspirate all liquid that attempts to contact the fiducial mark 34 (indicated by arrow 58). Or the liquid is prevented from coming into contact with the reference mark 34. In one embodiment, a combination of the above structures is employed in which both the gas inlet and the gas outlet are similarly disposed near the fiducial mark 34 to remove all the paths of liquid that attempt to contact the fiducial mark 34. Or preventing liquid from coming into contact with the fiducial mark 34.

  In this context, particular mention may be made of using the lithographic apparatus in IC manufacturing, but the lithographic apparatus described herein includes an integrated optical system, magnetic domain memory guides and detection patterns, a flat panel display, It should be understood that there are other applications such as liquid crystal displays (LCDs), thin film magnetic heads and the like. In such alternative applications, the use of the terms “wafer” and “die” herein may be considered synonymous with the general terms “substrate” and “target portion”, respectively. . The substrate cited herein may be processed before or after exposure, for example, with a track (typically a tool that applies a resist layer to the substrate and develops the exposed resist), a measuring tool and / or an inspection tool. Can do. If possible, the disclosure herein can be applied to these and other substrate processing instruments. In addition, the substrate can be processed one or more times, for example, to produce a multi-layer IC, and therefore the term substrate as used herein also refers to a substrate that includes a layer that has already been processed multiple times.

  As used herein, the terms “radiation light” and “beam” encompass all types of electromagnetic radiation, including ultraviolet (UV) radiation (eg, having a wavelength of 365, 248, 193, 157 or 126 nm). To do.

  Where the context allows, the term “lens” refers to any one or combination of various types of optical elements, including refractive and reflective optical elements.

  Although specific examples of the present invention have been described above, the present invention can be implemented by methods other than those described. For example, if possible, the present invention provides a computer program comprising one or more sequences of machine-readable instructions describing the method, or a data storage medium on which such a computer program is stored (eg, , Semiconductor memory, magnetic or optical disk).

  The present invention is applicable to any immersion lithographic apparatus (particularly, but not exclusively, an immersion lithographic apparatus of the type described above). Although an immersion liquid system using a gas seal has been described, other types of immersion liquid systems can be used. For example, an immersion liquid system using a movable seal. Furthermore, the immersion liquid used for insertion can have various components depending on the desired properties and the wavelength of the exposure radiation used. For 193 nm wavelengths, ultrapure water or water-based components are used, for which reason the immersion liquid is often referred to as water, and terms related to water such as hydrophilicity, hydrophobicity, moisture, etc. are used. The

  The above description is merely illustrative and is not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope described in the claims.

ADC Analog-to-digital converter BD Beam introduction system C Target part CO Condenser IF Position sensor IH Immersion hood IL Irradiation device IN Integration device M1, M2 Mask alignment mark MA Mask MT Mask table P1, P2 Substrate alignment mark PB Radiation Beam PL Projection system PM First positioning means PW Second positioning means SO Radiation source TIS Transmission image sensor W Substrate W1 Substrate table alignment marker WT Substrate table, that is, substrate stage 11 Reservoir 12 Seal member 14 First outlet 15 Inlet 30 Measuring station 32 Exposure station 34 Measuring sensor (reference mark)
40 Transmission image sensor (TIS)
42 Transmission Pattern 44 Phototube 52 Shutter 53 Space 54 Fan-Shaped Composite Shutter 55 Gas Inlet 56 Gas Jet or Gas Flow 57 Outlet

Claims (22)

A support structure configured to hold a patterning device configured to pattern the radiation beam according to a desired pattern;
A substrate table configured to hold a substrate;
A projection system configured to project the patterned beam of radiation onto a target portion of the substrate;
Measure a parameter relating to (a) the substrate table, (b) the substrate, (c) an image projected by the projection system, or (d) any combination of the items (a) to (c). A measurement system configured as follows:
A liquid supply system configured to supply liquid to a space between the substrate and the projection system;
A lithographic apparatus, comprising: a shield disposed near a portion of the measurement system and configured to shield the portion of the measurement system from liquid.   A lithographic apparatus according to claim 1, wherein the measurement system comprises a sensor.   The lithographic apparatus of claim 2, wherein the sensor comprises an alignment sensor, a level sensor, a transmitted image sensor, a lens interferometer, or any combination thereof.   The lithographic apparatus according to claim 2, wherein a part of the sensor includes a reference mark provided on the substrate table.   A lithographic apparatus according to claim 1, wherein the shield comprises a plate arranged in a part of the measurement system.   The lithographic apparatus of claim 5, further comprising a robotic arm configured to position the plate in the portion of the measurement system and to remove the plate from the portion of the measurement system.   6. A lithographic apparatus according to claim 5, wherein the plate is configured to keep the projection system in contact with a liquid as the substrate table is moved from below the projection system.   The lithographic apparatus of claim 7, further comprising a release mechanism configured to raise or hold the plate to keep the projection system in contact with a liquid.   The lithographic apparatus of claim 1, wherein the shield includes a shutter operable to isolate a portion of the measurement system from liquid.   The lithography according to claim 9, wherein the shutter includes a plate configured to open and close an opening in a void in the substrate table, and the portion of the measurement system is disposed in the void. apparatus.   The shutter includes a fan-shaped or compound shutter configured to open and close an opening of a void in the substrate table (the portion of the measurement system is provided in the void), and the measurement system is disposed in the void A lithographic apparatus according to claim 9, wherein said portion of is arranged.   The shield includes a gas inlet provided near a portion of the measurement system that generates a gas jet to substantially remove all liquid at or near the portion of the measurement system. A lithographic apparatus according to claim 1, wherein the lithographic apparatus is configured as follows.   The shield includes a vacuum outlet provided near the portion of the measurement system, the vacuum outlet configured to substantially inhale and remove all liquid near or near the portion of the measurement system. A lithographic apparatus according to claim 1.   A lithographic apparatus according to claim 1, wherein the measurement system can measure only one parameter of (a), (b) or (c). Projecting a patterned radiation beam onto a target portion of a substrate through a liquid present between the projection system and the substrate using a projection system; and
Measuring parameters relating to (a) a substrate table, (b) the substrate, (c) an image projected by the projection system, or (d) any combination of the items (a) to (c). A method for manufacturing a device, comprising shielding a part of a measurement system configured in (1) from a liquid.   The method of manufacturing a device according to claim 15, wherein shielding comprises placing a plate over the portion of the measurement system.   16. The method of manufacturing a device according to claim 15, wherein shielding includes isolating the portion of the measurement system from liquid by moving a shutter.   The method of manufacturing a device according to claim 15, wherein shielding includes closing an opening of a void in the substrate table, and the portion of the measurement system is disposed in the void.   16. The method of manufacturing a device of claim 15, wherein shielding includes generating a gas jet to remove substantially all of the liquid on or near the portion of the measurement system.   16. The method of manufacturing a device according to claim 15, wherein shielding includes aspirating off substantially all of the liquid on or near the portion of the measurement system.   The method of manufacturing a device according to claim 15, wherein the part of the measurement system includes a reference mark applied to the substrate table.   The device manufacturing method according to claim 15, wherein the measurement system measures only one parameter of the items (a), (b), and (c).

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